Fluorinated polymers are important items of commerce, being particularly noted, for instance, for their thermal and chemical resistance, and their often unusual surface properties. However, sometimes these unusual properties, as for example low adhesion to substrates, are often themselves also problems in the use of these polymers, so fluorinated (co)polymers with modified properties are constantly being sought.
Although it is known that certain functional groups, especially polar functional groups, can modify the properties of fluoropolymers, incorporation of these groups into fluoropolymers without sacrificing other desirable properties is often difficult for a variety of reasons. For example the required monomers may not copolymerize with fluorinated monomers or may cause other undesirable effects in a copolymerization, or incorporation of a monomer containing a polar group may adversely affect the chemical and/or thermal stability of the resulting polymer. While it is known that maleic anhydride or maleic acid are desirable comonomers for such polymerizations, practical methods for the incorporation of these monomers into fluoropolymers have been lacking, and therefore preparation and use of such polymers has languished.
Polymers containing relatively high proportions of fluorinated olefins, especially highly fluorinated olefins, have generally been grafted with MAN (or MAN copolymers) rather than being formed by copolymerizing with the MAN, see for instance M. Miller, et al., J. Appl. Polym. Sci., vol. 14, p. 257-266 (1970), German Patent Application 4,210,594, U.S. Pat. Nos. 5,576,106, 4,506,035, Australian Patent 550,961, and European Patent Applications 761,757 and 650,987. Many of these references also describe uses for such grafted polymers which are also applicable to the polymers herein.